Proper Torque to Tighten Rail Bolts - Diamond Pro

Crash said:
Of the 4 engineers (mechanical and civil) I ran this question by with the parameters I posted, all agreed that the torque specs "would" depend on the "wood". It stands to reason then that there is no one torque value that would apply to all tables.

A quick internet search found a website that says to tighten rails until "snug". Another says to use "light to medium torque"??? Another says when you "hear wood cracking they're too tight":eek: These site were generic pool table sites, not any particular brand.
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are you talking about the rail wood or slate liner material. rail wood is almost always poplar.
 
sdbilliards said:
are you talking about the rail wood or slate liner material. rail wood is almost always poplar.
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Donny....think Diamond....Brunswick....Olhausen....and SEARS...no one torque could be set for all tables....no way what-so-ever.

It's just OTLB up to his usual bs again....trust me...he knows better than that!
 
realkingcobra said:
Donny....think Diamond....Brunswick....Olhausen....and SEARS...no one torque could be set for all tables....no way what-so-ever.

It's just OTLB up to his usual bs again....trust me...he knows better than that!
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I know that there all different and common sense needs to come into play. Just curious on what the engineers say. I know from personal experience what torque setting should be in ordering to keep the rail sounding solid and not damaging hardware.
 
sdbilliards said:
I know that there all different and common sense needs to come into play. Just curious on what the engineers say. I know from personal experience what torque setting should be in ordering to keep the rail sounding solid and not damaging hardware.
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No engineer can give a correct answer to this question...unless there are specific perimeters set into place...ie: type of bolt, type of fastener, type and density of rail wood, type of washer, type of slate backing if used. Because of so many different kinds of rails out here...there is no one answer to this question. Diamond didn't even have a torque value for their rails...until I established one back in 2000;)
 
Sorry, I promised myself I'd never post in this area because I'm not a table mechanic. I'll also admit here I'm not a mechanical engineer but work with them everyday selling torque wrenches with capacities between a couple in/oz to 65,000 ft/lbs. Yes 65K. Even though Torque is my gig business wise I never recommend a specific value and IMO no respectable engineer would without thorough research on the specific joint. Too many things to consider, some Cobra mentioned. So listen to Cobra. There is no way to set a standard torque for all tables. Probably not even within the same manufacturer. Many times engineers will ask how accurate and repeatable my tools are. The smart **s reply is How accurate and repeatable are the joints we're bolting up?

Looking at GENERIC torque tension charts 10-15 ft/lbs seems to be a reasonable starting point. A 50% spread. If we were talking about bolting 2 pieces of metal and a washer 19ft/lbs is a generic torque value for a 3/8" dia. Grade 2 bolt. Grade 5 you're looking at 30 ft/lbs. I'd be surprised if GR5 is ever used for a table.

The idea of torque as a method to properly install fasteners is the easy way to achieve a specific clamp load. Clamp load is calculated based on many factors one of which is the tensile strength of the fasteners. A properly installed fastener is loaded to the point that there's a slight amount of stretch in the bolt. Steel is elastic like a rubber band and is trying to recover to its original length. This attempt is basically what gives us and maintains the clamp load. We could lose that stretch due to relaxation because we're compressing wood. If we apply too much torque the wood could continue to move after the bolt has been torqued so at a later time, minutes or days later the bolt is now lose. Think T-Rail.

To the OP: Do Not Loosen Your Bolts With a Torque Wrench. There's only one torque wrench manufacturer I'm aware of where this is OK. Everybody else loss of calibration and or permanent damage will occur.

Back to My Cave
 
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3kushn said:
Sorry, I promised myself I'd never post in this area because I'm not a table mechanic. I'll also admit here I'm not a mechanical engineer but work with them everyday selling torque wrenches with capacities between a couple in/oz to 65,000 ft/lbs. Yes 65K. Even though Torque is my gig business wise I never recommend a specific value and IMO no respectable engineer would without thorough research on the specific joint. Too many things to consider, some Cobra mentioned. So listen to Cobra. There is no way to set a standard torque for all tables. Probably not even within the same manufacturer. Many times engineers will ask how accurate and repeatable my tools are. The smart **s reply is How accurate and repeatable are the joints we're bolting up?

Looking at GENERIC torque tension charts 10-15 ft/lbs seems to be a reasonable starting point. A 50% spread. If we were talking about bolting 2 pieces of metal and a washer 19ft/lbs is a generic torque value for a 3/8" dia. Grade 2 bolt. Grade 5 you're looking at 30 ft/lbs. I'd be surprised if GR5 is ever used for a table.

The idea of torque as a method to properly install fasteners is the easy way to achieve a specific clamp load. Clamp load is calculated based on many factors one of which is the tensile strength of the fasteners. A properly installed fastener is loaded to the point that there's a slight amount of stretch in the bolt. Steel is elastic like a rubber band and is trying to recover to its original length. This attempt is basically what gives us and maintains the clamp load. We could lose that stretch due to relaxation because we're compressing wood. If we apply too much torque the wood could continue to move after the bolt has been torqued so at a later time, minutes or days later the bolt is now lose. Think T-Rail.

To the OP: Do Not Loosen Your Bolts With a Torque Wrench. There's only one torque wrench manufacturer I'm aware of where this is OK. Everybody else loss of calibration and or permanent damage will occur.

Back to My Cave
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I got a kick out of your post...good explaination...I must have been speaking German or something....because I thought I did a good job of explaining the same thing you said:D rep to you for translating my post in to English:D

Glen
 
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